Effects of different rotating speeds on friction and wear behavior of die cast magnesium alloy AZ91D have been investigated by using a MM-200 abrasive tester, and the wear mechanism has been described. The results show that with increasing the rotating speed, the weight loss of the alloy can be increased and the friction coefficient can be decreased. The oxidation wear and abrasive wear are dominant in the wear behavior of the alloys at low rotating speed while delamination wear and melted wear are dominant in ones with the increase of wear time at high rotating speed. The wear resistant of the alloys at high rotating speed can be greatly improved by T6 heat treatment.